Strain gauge stabilization in a surgical device

ABSTRACT

An adapter assembly is provided and includes a tubular housing having a proximal end portion and a distal end portion and defining a longitudinal axis; a load sensing assembly disposed within the tubular housing in contact between a proximal surface and a distal surface, the proximal and distal surfaces perpendicular to the longitudinal axis, the load sensing assembly configured to measure a load exerted on the tubular housing, the load sensing assembly including a sensor body; and a gimbal disposed between a sensor body surface and at least one of the proximal surface or the distal surface, the gimbal configured to isolate the sensor body from the load exerted in a plane perpendicular to the longitudinal axis.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/815,563 filed Mar. 8, 2019 and claims the benefit of and priority to U.S. Provisional Patent Application Ser. No. 62/881,992, filed Aug. 2, 2019, the entire disclosure of which is incorporated by reference herein.

BACKGROUND Technical Field

The present disclosure relates to surgical devices. More specifically, the present disclosure relates to handheld electromechanical surgical systems for performing surgical procedures having reusable components with load sensing devices.

2. Background of Related Art

One type of surgical device is a circular clamping, cutting and stapling device. Such a device may be employed in a surgical procedure to reattach rectum portions that were previously transected, or similar procedures. Conventional circular clamping, cutting, and stapling devices include a pistol or linear grip-styled structure having an elongated shaft extending therefrom and a staple cartridge supported on the distal end of the elongated shaft. In this instance, a physician may insert the loading unit portion of the circular stapling device into a rectum of a patient and maneuver the device up the colonic tract of the patient toward the transected rectum portions. The loading unit includes a cartridge assembly having a plurality of staples. Along the proximal portion of the transected colon, an anvil assembly can be purse-stringed therein. Alternatively, if desired, the anvil portion can be inserted into the colon through an incision proximal to the transected colon. The anvil and cartridge assemblies are approximated toward one another and staples are ejected from the cartridge assembly toward the anvil assembly thereby forming the staples in tissue to affect an end-to-end anastomosis, and an annular knife is fired to core a portion of the clamped tissue portions. After the end-to-end anastomosis affected, the circular stapling device is removed from the surgical site.

A number of surgical device manufacturers have also developed proprietary powered drive systems for operating and/or manipulating the end effectors. The powered drive systems may include a powered handle assembly, which may be reusable, and a disposable end effector that is removably connected to the powered handle assembly.

Many of the existing end effectors for use with existing powered surgical devices and/or handle assemblies are driven by a linear driving force. For example, end effectors for performing endo-gastrointestinal anastomosis procedures, end-to-end anastomosis procedures and transverse anastomosis procedures, are actuated by a linear driving force. As such, these end effectors are not compatible with surgical devices and/or handle assemblies that use rotary motion.

In order to make the linear driven end effectors compatible with powered surgical devices that use a rotary motion to deliver power, a need exists for adapters to interconnect the linear driven end effectors with the powered rotary driven surgical devices. These adapters may also be reusable, and as such, need to able to withstand multiple sterilization cycles. As these adapters are becoming more sophisticated and include various electronic components, there is a need for electronic components disposed within the adapters that can withstand multiple autoclave cycles.

SUMMARY

Powered surgical devices may include various sensors for providing feedback during their operation. However, one limitation of the electronics and sensors used in the sterile environment of the operating room is that they need to be designed to withstand multiple cleaning and autoclave cycles. In order to gather information on the mechanical forces applied by the powered surgical devices, load sensing devices, such as load cells, are disposed on one or more mechanical components of the powered surgical device and/or adapters coupled thereto.

Powered surgical devices utilizing strain gages enable the user to have force awareness feedback which can enable a number of advantages. Benefits of force monitoring include anvil detection, staple detection, cutting, controlled tissue compression to avoid tissue damage while maximizing staple formation consistency, excessive load adjustment of stroke to optimized staple formation, tissue thickness identification, and the like. Due to the sensitivity of the load sensing devices, any unintended forces or strains on the gage can negatively impact the accuracy of the device.

The present disclosure provides for an adapter assembly having a loading sensing device and a gimbal disposed in the constraint condition of the load sensing device. The load sensing device is disposed between two parallel opposing surfaces and measures the strain imparted thereto due to actuation of various actuation assemblies within the adapter assembly. The position of the load sensing device between two opposing parallel surfaces introduces off-axis variations in the orientation of a trocar assembly, which changes the load on the load sensing device and consequently the accuracy of the measurements. Placement of the gimbal allows the load sensing device to be loaded only in a uni-axial strain, namely, in a longitudinal direction, without additional moments or off-axis loads, namely, in a plane perpendicular to the longitudinal axis. The gimbal is a dual-rocking mechanism that allows rotation at the point of loading on the load sensing device so that changes in orientation of the trocar assembly do not affect the loading condition of the load sensing device.

Load sensing devices are also coupled to signal processing and conditioning circuit that are separately packaged from the load sensing devices. These circuits process the change in resistance of the load sensing devices and determine the load applied thereto. In particular, components of signal processing circuits are usually disposed on printed circuit boards (“PCB”) housed with other electronic and electric components of powered surgical devices. Remote placements of these circuit components away from the load sensing devices is due to their size and shape, which prevent the PCB from being in close proximity to the load sensing devices. Accordingly, these circuits are connected to the load sensing devices through wired connections, which involve longer leads (e.g., flexible printed circuit traces over 10 centimeters) for transmitting analog signals from the load sensing devices to the signal processing circuit. Longer wired connections can result in signal loss and also increase the chances of failure due to exposure of these leads to disinfecting and sterilization cycles. Harsh environments from disinfecting solutions and residual moisture from the autoclaving processes breaks down the components and coatings in flex circuits, thereby causing signal degradation. Further, in surgical devices where saline irrigation is utilized, the saline can further breakdown of mechanical integrity of these circuits resulting in signal degradation.

In addition, the separation between the load sensing devices and the signal processing circuitry also affects fidelity of analog sense signals transmitted from the load sensing devices. The analog voltage signals are low voltage signals and are therefore more susceptible to interference of the load measured by the load sensing devices due to water ingress in the PCB, solder connections, and/or traces, small contamination including solder flux and autoclave mineral deposits, as well as radio frequency interference due to long conductor travel length. Remote placement of signal processing circuits also results in lower bit resolution. Furthermore, conventional signal processing circuits used with load sensing devices have no ability to compensate for zero balance fluctuations in load sensing devices due to inconsistencies of sensor bodies housing the load sensing devices (e.g., during manufacture and assembly of the sensors). As used herein, the term “zero balance” denotes a baseline signal from a load sensing device corresponding to a condition in which the load sensing device is unloaded.

The present disclosure provides for a combined load sensing assembly having one or more load sensing devices and a signal processing circuit disposed within a hermetically sealed housing of the sensor. This obviates the problem of transmitting analog load sensing signals along long leads and protects the load sensing devices and the signal processing circuit from exposure to elements including sterilization cycles (e.g., autoclaving). In addition, the signal processing circuit is programmable to optimize the sensor signals by adjusting gain and offset values of sensor signals.

Conventional load sensing devices that utilize strain gauge technology typically suffer from the lack of adjustability or tuning of the load sensing devices. In particular, variations in the load sensing devices, tolerances in sensor bodies, placement of the load sensing devices, and other factors, contribute to zero balance variations, which result in variable zero balance values across the lot of load sensing devices. Unfortunately, in conventional load sensing devices zero balance cannot be adjusted for each individual load sensing device. The present disclosure provides a signal processing circuit that may be programmed to adjust zero balance after the load sensor is manufactures and/or assembled.

The present disclosure provides multiple embodiments, each of which includes multiple aspects. Various aspects of the embodiments are interchangeable among the disclosed embodiments. According to one embodiment of the present disclosure, an adapter assembly includes: a tubular housing having a proximal end portion and a distal end portion and defining a longitudinal axis. The adapter assembly also includes a load sensing assembly disposed within the tubular housing in contact between a proximal surface and a distal surface, the proximal and distal surfaces perpendicular to the longitudinal axis, the load sensing assembly configured to measure a load exerted on the tubular housing, the load sensing assembly including a sensor body. The adapter assembly includes a gimbal disposed between a sensor body surface and at least one of the proximal surface or the distal surface, the gimbal configured to isolate the sensor body from the load exerted in a plane perpendicular to the longitudinal axis.

According to another embodiment of the present disclosure, a surgical device includes: a handle assembly including a controller; an adapter assembly having: a tubular housing having a proximal end portion and a distal end portion and defining a longitudinal axis; a load sensing assembly disposed within the tubular housing in contact between a proximal surface and a distal surface, the proximal and distal surfaces perpendicular to the longitudinal axis, the load sensing assembly configured to measure a load exerted on the tubular housing. The load sensing assembly includes a sensor body; and a gimbal disposed between a sensor body surface and at least one of the proximal surface or the distal surface, the gimbal configured to isolate the sensor body from the load exerted in a plane perpendicular to the longitudinal axis; and a surgical end effector configured to couple to the distal end portion of the adapter assembly.

According to one aspect of any of the above embodiments, the load sensing assembly further includes: a load sensor circuit disposed within the sensor body. The adapter assembly may also include a signal processing circuit disposed within the sensor body and electrically coupled to the load sensor circuit.

According to another aspect of any of the above embodiments, the gimbal has a tubular shape having a width, a thickness, and a radius. The proximal surface of the gimbal and the distal surface of the gimbal includes a pair of peaks. Each of the proximal surface of the gimbal and the distal surface defines a waveform having a wavelength defined by πr, where r is the radius of the tubular shape having an amplitude that is equal to the thickness of the tubular shape. The gimbal also includes a proximal surface and a distal surface, each of the proximal surface of the gimbal and the distal surface of the gimbal has an undulating shape. The sensor body includes a tubular portion and the gimbal is disposed over the tubular portion.

According to one embodiment of the present disclosure, an adapter assembly includes a tubular housing having a proximal end portion and a distal end portion and defining a longitudinal axis. The adapter assembly also includes a load sensing assembly disposed within the tubular housing in contact between a proximal surface and a distal surface. Each of the proximal surface and the distal surface is perpendicular to the longitudinal axis. The load sensing assembly is configured to measure a load exerted on the tubular housing. The load sensing assembly also includes a sensor body, wherein at least one of the proximal surface or the distal surface includes a first surface feature and the sensor body includes a second surface feature engaging the first surface feature.

According to one aspect of the above embodiment, the first surface feature is a convex surface feature and the second surface feature is a concave surface feature. The first surface feature may be a ridge having a first curved cross-section. The second surface feature may be a groove having a second curved cross-section. The first curved cross-section and the second curved cross-section have the same radius. The sensory body is configured to pivot about a pivot axis that is transverse to a longitudinal axis defined by the sensory body. The pivot axis is defined by the ridge and passes through each of center of the first curved cross-section and the second curved cross-section.

According to another aspect of the above embodiment, the first surface feature is a concave surface feature and the second surface feature is a convex surface feature. The first surface feature is a groove having a first curved cross-section. The second surface feature is a ridge having a second curved cross-section. The first curved cross-section and the second curved cross-section have the same radius. The sensory body is configured to pivot about a pivot axis that is transverse to a longitudinal axis defined by the sensory body. The pivot axis is defined by the ridge and passes through each of center of the first curved cross-section and the second curved cross-section.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present disclosure are described herein with reference to the accompanying drawings, wherein:

FIG. 1 is a perspective view of a handheld surgical device, an adapter assembly, an end effector having a reload and an anvil assembly according to an embodiment of the present disclosure;

FIG. 2 is a perspective view illustrating a connection of the adapter assembly and the handle assembly of FIG. 1 according to an embodiment of the present disclosure;

FIG. 3 is perspective view of internal components of the handle assembly according to an embodiment of the present disclosure;

FIG. 4 is a perspective view of the adapter assembly of FIG. 1 without the reload according to an embodiment of the present disclosure;

FIG. 5 is a side, cross-sectional view, of the reload of FIG. 1 according to an embodiment of the present disclosure;

FIG. 6A is a perspective view of the distal end portion of the adapter assembly according to an embodiment of the present disclosure;

FIG. 6B is a cross-sectional view of the distal end portion of the adapter assembly according to an embodiment of the present disclosure;

FIG. 7 is a perspective view of an electrical assembly of the adapter assembly of FIG. 1 according to an embodiment of the present disclosure;

FIG. 8 is a perspective view of a distal portion of the electrical assembly according of FIG. 7 to an embodiment of the present disclosure;

FIG. 9 is a perspective top view of a load sensing assembly of the electrical assembly of FIG. 7 according to an embodiment the present disclosure;

FIG. 10 is a perspective bottom view of the load sensing assembly of FIG. 9;

FIG. 11 is a cross-sectional, side view of the load sensing assembly of FIG. 9;

FIG. 12 is a perspective top view of the load sensing assembly of FIG. 8 without a cover;

FIG. 13 is a perspective top view of the load sensing assembly of FIG. 8 without a load sensor circuit and a signal processing circuit;

FIG. 14 is a perspective top view of a cover of the load sensing assembly of FIG. 9 according to an embodiment the present disclosure;

FIG. 15 is a perspective bottom view of the cover of FIG. 14;

FIG. 16 is a side view of a gimbal disposed over a portion of the load sensing assembly of FIG. 8 according to the present disclosure.

FIG. 17 is a top view of a load sensing assembly and a support block according to an embodiment of the present disclosure;

FIG. 18 is a perspective view of the load sensing assembly and the support block of FIG. 17;

FIG. 19 is a top view of a load sensing assembly and a support block according to an embodiment of the present disclosure;

FIG. 20 is a perspective view of the load sensing assembly and the support block of FIG. 19;

FIG. 21 is a top view of a load sensing assembly and a support block according to an embodiment of the present disclosure;

FIG. 22 is a perspective view of the load sensing assembly and the support block of FIG. 21;

FIG. 23 is a perspective view of a load sensing assembly, a conforming gimbal, and a support block according to an embodiment of the present disclosure;

FIG. 24 is a cross-sectional view of a pin connector of the load sensing assembly of FIG. 9 according to an embodiment the present disclosure;

FIG. 25 is a top, schematic view of a load sensor circuit and a signal processing circuit according to an embodiment the present disclosure; and

FIG. 26 is an electrical schematic drawing of the signal processing circuit of FIG. 25 according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

Embodiments of the present disclosure are now described in detail with reference to the drawings in which like reference numerals designate identical or corresponding elements in each of the several views. The embodiments may be combined in any manner consistent with the functionality of the apparatus and/or method disclosed herein. As used herein, the term “clinician” refers to a doctor, a nurse or any other care provider and may include support personnel. Throughout this description, the term “proximal” will refer to the portion of the device or component thereof that is closer to the clinician and the term “distal” will refer to the portion of the device or component thereof that is farther from the clinician. The term “substantially equal to” denotes that two values are ±5% of each other. Additionally, in the drawings and in the description that follows, terms such as front, rear, upper, lower, top, bottom, and similar directional terms are used simply for convenience of description and are not intended to limit the disclosure. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the present disclosure in unnecessary detail.

The present disclosure relates to powered surgical devices having electronic sensors for monitoring mechanical strain and forces imparted on components of the powered surgical devices. More particularly, this disclosure relates to load measuring sensors including load sensing devices as well as analog and digital circuitry that are hermetically sealed such that the load sensors are configured to resist harsh environments. In the event that electrical connections of the powered surgical devices are compromised during use, measurement signals output by the sensors of the present disclosure remain unaltered. In addition, the sensors are programmable allowing for adjustments to gain and offset values in order to optimize the measurement signals.

With reference to FIG. 1, a powered surgical device 10 includes a handle assembly 20, which is configured for selective connection with an adapter assembly 30, which in turn, is configured for selective connection with an end effector, such as an annular reload 40. Although generally referred to as being a powered surgical device, it is contemplated that the surgical device 10 may be a manually actuated and may include various configurations.

The handle assembly 20 includes a handle housing 22 having a lower housing portion 24, an intermediate housing portion 26 extending from and/or supported on a portion of the lower housing portion 24, and an upper housing portion 28 extending from and/or supported on a portion of the intermediate housing portion 26. As shown in FIG. 2, a distal portion of the upper housing portion 28 defines a nose or connecting portion 28 a that is configured to accept a proximal end portion 30 b of the adapter assembly 30.

With reference to FIG. 3, the handle assembly 20 includes one or more motors 36 which are coupled to a battery 37. The handle assembly 20 also includes a main controller 38 for operating the motors 36 and other electronic components of the handle assembly 20, the adapter assembly 30, and the reload 40. The motors 36 are coupled to corresponding drive shafts 39 (FIG. 2), which are configured to engage sockets 33 on the proximal end portion 30 b, such that rotation of the drive shafts 39 is imparted on the sockets 33. The actuation assembly 52 (FIG. 6B) is coupled to a respective socket 33. The actuation assembly 52 is configured to transfer rotational motion of the sockets 33 into linear motion and to actuate the reload 40 (FIG. 1) along with the anvil assembly 58.

With reference to FIG. 4, the adapter assembly 30 includes a tubular housing 30 a that extends between a proximal end portion 30 b that is configured for operable connection to the connecting portion 28 a of the handle assembly 20 and an opposite, distal end portion 30 c that is configured for operable connection to the reload 40. In this manner, the adapter assembly 30 is configured to convert a rotational motion provided by the handle assembly 20 into axial translation useful for advancing/retracting a trocar member 50 slidably disposed within the distal end portion 30 c of the adapter assembly 30 (FIG. 5) for firing staples of the reload 40.

With reference to FIG. 2, the connecting portion 28 a includes an electrical receptacle 29 having a plurality of electrical contacts 31, which are in electrical communication with electronic (e.g., main controller 38) and electrical components (e.g., battery 37) of the handle assembly 20. The adapter assembly 30 includes a counterpart electrical connector 32 that is configured to engage the electrical receptacle 29. The electrical connector 32 also includes a plurality of electrical contacts 34 that engage and electrically connect to their counterpart electrical contacts 31.

With reference to FIG. 4, the trocar member 50 is slidably disposed within the tubular housing 30 a of the adapter assembly 30 and extends past the distal end portion 30 c thereof. In this manner, the trocar member 50 is configured for axial translation, which in turn, causes a corresponding axial translation of an anvil assembly 58 (FIG. 1) of the reload 40 to fire the staples (not shown) disposed therein. The trocar member 50 includes a proximal end which is coupled to the tubular housing 30 a of the adapter assembly 30. A distal end portion of the trocar member 50 is configured to selectively engage the anvil assembly 58 of the reload 40 (FIG. 4). In this manner, when the anvil assembly 58 is connected to the trocar member 50, as will be described in detail hereinbelow, axial translation of the trocar member 50 in the first direction results in an opening of the anvil assembly 58 relative to the reload 40, and axial translation of the trocar member 50 in a second, opposite direction, results in a closing of the anvil assembly 58 relative to the reload 40.

As illustrated in FIGS. 1 and 5, the reload 40 is configured for operable connection to adapter assembly 30 and is configured to fire and form an annular array of surgical staples, and to sever a ring of tissue. The reload 40 includes a housing 42 having a proximal end portion 42 a and a distal end portion 42 b and a staple cartridge 44 fixedly secured to the distal end portion 42 b of the housing 42. The proximal end portion 42 a of the housing 42 is configured for selective connection to the distal end portion 30 c of the adapter assembly 30 and includes a means for ensuring the reload 40 is radially aligned or clocked relative to the adapter assembly 30.

With reference to FIG. 5, the housing 42 of the reload 40 includes an outer cylindrical portion 42 c and an inner cylindrical portion 42 d. The outer cylindrical portion 42 c and the inner cylindrical portion 42 d of the reload 40 are coaxial and define a recess 46. The recess 46 of the reload 40 includes a plurality of longitudinally extending ridges or splines 48 projecting from an inner surface thereof which is configured to radially align the anvil assembly 58 relative to the reload 40 during a stapling procedure.

With reference now to FIGS. 6A-8, adapter assembly 30 includes an electrical assembly 60 disposed therewithin, and configured for electrical connection with and between handle assembly 20 and reload 40. Electrical assembly 60 provides for communication (e.g., identifying data, life-cycle data, system data, load sense signals) with the main controller 38 of the handle assembly 20 through the electrical receptacle 29.

Electrical assembly 60 includes the electrical connector 32, a proximal harness assembly 62 having a ribbon cable, a distal harness assembly 64 having a ribbon cable, a load sensing assembly 66, and a distal electrical connector 67. The electrical assembly 60 also includes the distal electrical connector 67 which is configured to selectively mechanically and electrically connect to a chip assembly (not shown) of reload 40.

Electrical connector 32 of electrical assembly 60 is supported within the proximal end portion 30 b of the adapter assembly 30. Electrical connector 32 includes the electrical contacts 34 which enable electrical connection to the handle assembly 20. Proximal harness assembly 62 is electrically connected to the electrical connector 32 disposed on a printed circuit board 35.

Load sensing assembly 66 is electrically connected to electrical connector 32 via proximal and distal harness assemblies 62, 64. Load sensing assembly is also electrically connected to distal harness assembly 64 via a sensor flex cable. As shown in FIGS. 6A and 6B, an actuation assembly 52, which is coupled to the trocar member 50, extends through the load sensing assembly 66. The load sensing assembly 66 provides strain measurements imparted on the adapter assembly 30 during movement of the trocar member 50 when coupled to the anvil assembly 58 during clamping, stapling, cutting, and other mechanical actuations.

For a detailed description of an exemplary powered surgical stapler including an adapter assembly and a reload, reference may be made to commonly owned U.S. Patent Application Publication No. 2016/0310134 to Contini et al., titled “Handheld Electromechanical Surgical System,” filed Apr. 12, 2016, incorporated in its entirety by reference hereinabove.

With reference to FIGS. 9-13, the load sensing assembly 66 includes a sensor body 68 having a platform 70 and a tubular portion 72 extending from the platform 70 by a distance “d”. The sensor body 68 also defines a lumen 73 through the platform 70 and the tubular portion 72, thereby separating the platform 70 into a first portion 74 and a second portion 76. The lumen 73 allows for the passage of the actuation assembly 52 therethrough. The sensor body 68 may be formed from any suitable material, such as stainless steel, that allows for the sensor body 68 to be elastically deformed when stressed. In embodiments, the sensor body 68 may be fabricated from stainless steel, such as 17-4 stainless steel heat-treated to H-900 standard.

The tubular portion 72 may have any suitable shape such as cylindrical, faceted, or combinations thereof as shown in FIG. 10. More specifically, the tubular portion 72 includes a plurality of side walls 72 a interconnected by fillet corners 72 b. The tubular portion 72 also includes a bottom contact surface 72 c. The platform 70 also includes a top (e.g., distal) surface 78 and a bottom (e.g., proximal) surface 80 (FIG. 10) as well as a first slot 82 defined within the first portion 74 of the platform 70 and a second slot 84 defined through the second portion 76 of the platform 70. Slots 82 and 84 work in combination with the design of sensor body 68 to provide uniform bending when loaded. The uniform loading and resulting strain output causes a load sensor circuit 86 (FIGS. 11 and 12) of the load sensing assembly 66 to provide provides linear strain output at the first portion 74 of the platform 70, which is measured by a load sensor circuit 86 secured to the first portion 74 and covered by a cover 88 as shown in FIG. 11.

With reference to FIGS. 6A and 6B, the load sensing assembly 66 is disposed between a support block 54 and a connector sleeve 56. In particular, the tubular portion 72 of the sensor body 68 on the bottom contact surface 72 c rests on the support block 54 and the top surface 78 of the platform 70 abuts a proximal end of the connector sleeve 56. During operation of the surgical device 10, namely, clamping, stapling, and cutting, the sensor body 68 is elastically deformed (similar to a support beam) in proportion to the forces applied to the support block 54 and the connector sleeve 56. In particular, deflection of the sensor body 68 applies a force to the load sensor circuit 86 (FIGS. 11 and 12), which is deformed causing its electrical resistance to increase, which is reflected in its measurement signal. A change in a baseline of the measurement signal is indicative of the forces being imparted on the support block 54 and the connector sleeve 56, which are generally descriptive of the forces encountered during clamping, stapling, and cutting.

With reference to FIG. 16, the adapter assembly 30 also includes a gimbal 81 disposed over the tubular portion 72. The gimbal 81 may be formed from any high tensile strength material, such as stainless steel and other metals. The gimbal 81 has a tubular shape having a width “d”, a thickness “t”, and a radius “r”. The width “d” is substantially equal to the distance “d”. The gimbal 81 includes a top (e.g., distal) surface 83 a and a bottom (e.g., proximal) surface 83 b. Each of the top surface 83 a and the bottom surface 83 b has an undulating shape having one or more waveforms 85 a and 85 b, respectively. The waveforms 85 a and 85 b may have a wavelength that is based on the radius “r” of the gimbal 81, namely, “πr”, and an amplitude that is substantially equal to the thickness “t” of the gimbal 81. Each of the waveforms 85 a and 85 b includes a plurality of peaks 87 a and 87 b, respectively.

The gimbal 81 is disposed between the bottom surface 80 of the platform 70 and the support block 54. More specifically, the top surface 83 a of the gimbal 81 is in contact with the bottom surface 80 of the platform 70 and the bottom surface 83 b of the gimbal 81 is in contact with a distal surface of the support block 54. Since each of the top surface 83 a and the bottom surface 83 b includes the peaks 87 a and 87 b, respectively, the peaks 87 a and 87 b are in contact with their respective surfaces, namely, bottom surface 80 and the support block 54.

As the load sensing assembly 66 is compressed between the support block 54 and the connector sleeve 56, the support block 54 applies pressure on the gimbal 81. In additional to longitudinal pressure, lateral movement of the support block 54 is negated by the gimbal 81. This is due to the dual-rocking configuration of the gimbal 81 due to the top and bottom surfaces 83 a and 83 b having undulating shapes. In particular, the gimbal 81 is rotated about the point of contact between the top and bottom surfaces 83 a and 83 b and the bottom surface 80 of the sensor body 68 and the support block 54, namely, the peaks 87 a and 87 b. Inclusion of two peaks 87 a and 87 b on each of the top and bottom surfaces 83 a and 83 b provides for isolation of the sensor body 68 by preventing off-axis loads, namely, stresses imparted in a plane perpendicular to a longitudinal axis X-X defined by the sensor body 68, being measured by the load sensor circuit 86. This allows for the load sensor circuit 86 to measure only the stresses imparted in the longitudinal direction, which provides for an accurate measurement.

In embodiments, the gimbal 81 may be disposed distally of the sensor body 68. More specifically, the gimbal 81 may be disposed between the connector sleeve 56 and the top surface 78 of the sensor body 68. Accordingly, the tubular portion 72 may be disposed on the top surface 78 rather than the bottom surface 80. In a distal configuration, the gimbal 81 may be disposed around the tubular portion 72 and functions in the same way as a proximal configuration described above.

In further embodiments, the sensor body 68 may be disposed between two gimbals 81, namely, between the support block 54 and/or the connector sleeve 56. In yet further embodiments, the tubular portion 72 may be any suitable fixation structure such as a post, a depression, and the like, which would allow for securing of the gimbal 81 to the sensory body 68.

In additional embodiments, the gimbal 81 may have flat top and bottom surfaces 83 a and 83 b and the surfaces in contact with the gimbal, e.g., the bottom surface 80 of the platform 70 and the distal surface of the support block 54, may have an undulating shape having one or more waveforms 85 a and 85 b, as described above.

With reference to FIGS. 17 and 18, the adapter assembly 30 may include a support block 154 and a sensor body 168. The support block 154 and the sensor body 168 may be used in lieu of the support block 54 and the sensor body 68 and the gimbal 81 to isolate the sensor assembly 66. The support block 154 includes a convex surface feature, namely, a ridge 156 having a curved cross-section. The sensor body 168 includes a counterpart concave surface feature, namely, a curved groove 170. The curved groove 170 is formed on a proximal surface of the tubular portion 72. The curved groove 170 and the ridge 156 are disposed along a pivot axis Y-Y that is transverse to the longitudinal axis X-X. The curved groove 170 and the ridge 156 have substantially the same radius r2 such that the ridge 156 fits within the curved groove 170, allowing sensor body 168 to pivot about the pivot axis Y-Y relative to the support block 154. The pivot axis Y-Y passes through a center of an arc defining the ridge 156 and the curved groove 170. The pivoting configuration of the ridge 156 and the curved groove 170 provides for isolation of the sensor body 168 by preventing off-axis loads, namely, stresses imparted in a plane perpendicular to a longitudinal axis X-X that lie on the axis Y-Y, being measured by the load sensor circuit 86. This allows for the load sensor circuit 86 to measure only the stresses imparted in the longitudinal direction, which provides for an accurate measurement of the strain imparted on the adapter assembly 30.

With reference to FIGS. 19 and 20, the adapter assembly 30 may include a support block 254 and a sensor body 268. The support block 254 and the sensor body 268 may be used in lieu of the support block 54 and the sensor body 68 and the gimbal 81 to isolate the sensor assembly 66. The embodiment of FIGS. 19 and 20 is similar to the embodiment of FIGS. 17 and 18 with the location of the concave and convex surfaces being reversed. In particular, the support block 254 includes a concave surface feature, namely, a curved groove 270 having a curved cross-section. The sensor body 268 includes a counterpart convex surface feature, namely, a ridge 256. The ridge 256 and the curved groove 270 are disposed along a pivot axis Y-Y that is transverse to the longitudinal axis X-X. The ridge 256 and the curved groove 270 have substantially the same radius r2 such that the curved groove 270 fits within the ridge 256, allowing sensor body 268 to pivot about the pivot axis Y-Y relative to the support block 254. The pivoting configuration of the curved groove 270 and the ridge 256 provides for isolation of the sensor body 268 by preventing off-axis loads, namely, stresses imparted in a plane perpendicular to a longitudinal axis X-X that lie on the axis Y-Y, being measured by the load sensor circuit 86. This allows for the load sensor circuit 86 to measure only the stresses imparted in the longitudinal direction, which provides for an accurate measurement of the strain imparted on the adapter assembly 30.

With reference to FIGS. 21 and 22, the adapter assembly 30 may include a support block 354 and a sensor body 368. The support block 354 and the sensor body 368 may be used in lieu of the support block 54 and the sensor body 68 and the gimbal 81 to isolate the sensor assembly 66. The embodiment of FIGS. 21 and 22 is similar to the embodiment of FIGS. 19 and 20. In particular, the support block 354 also includes a concave surface feature, namely, a curved groove 370 having a curved cross-section. In addition, a gimbal 181 is disposed between the support block 354 and the sensor body 368. The gimbal 181 includes a counterpart convex surface feature, namely, a ridge 356 that is disposed on a first contact surface 181 a. The ridge 356 and the curved groove 370 are disposed along a pivot axis Y-Y that is transverse to the longitudinal axis X-X. The ridge 356 and the curved groove 370 have substantially the same radius r2 such that the curved groove 370 fits within the ridge 356, allowing gimbal 181 to pivot about the pivot axis Y-Y relative to the support block 354.

In addition, the gimbal 181 also includes one or more concave surface features, namely, a curved groove 183 having a curved cross-section. The curved groove 183 is disposed on a second contact surface 181 b, which is opposite the first contact surface 181 a. The sensor body 368 includes a counterpart convex surface feature, namely, a ridge 456. The ridge 456 and the curved groove 183 are disposed along a pivot axis Z-Z that is transverse to the longitudinal axis X-X and the pivot axis Y-Y. The ridge 456 and the curved groove 183 have substantially the same radius r3 such that the curved groove 183 fits within the ridge 456, allowing gimbal 181 to pivot about the pivot axis Z-Z relative to the sensor body 368. The dual pivoting configuration of the gimbal 181 with respect to the support block 354 and the sensory body 368 provide for isolation of the sensor body 268 by preventing off-axis loads, namely, stresses imparted in a plane perpendicular to a longitudinal axis X-X that lie on the Y-Y and Z-Z axes, being measured by the load sensor circuit 86. This allows for the load sensor circuit 86 to measure only the stresses imparted in the longitudinal direction, which provides for an accurate measurement of the strain imparted on the adapter assembly 30.

With reference to FIG. 23, another embodiment of a gimbal 281 is shown. With reference to FIG. 23, the adapter assembly 30 also includes a gimbal 281 disposed over the tubular portion 72. The gimbal 281 may be formed from any elastomeric, conformable material such as silicone rubber. Suitable silicone rubbers include room temperature vulcanization (RTV) silicone rubbers; high temperature vulcanization (HTV) silicone rubbers and low temperature vulcanization (LTV) silicone rubbers. These rubbers are known and readily available commercially such as SILASTIC® 735 black RTV and SILASTIC® 732 RTV, both from Dow Corning; and 106 RTV Silicone Rubber and 90 RTV Silicone Rubber, both from General Electric. Other suitable silicone materials include the silanes, siloxanes (e.g., polydimethylsiloxanes) such as, fluorosilicones, dimethyl silicones, liquid silicone rubbers such as vinyl cross-linked heat curable rubbers or silanol room temperature cross-linked materials, and the like. The gimbal 81 includes a top (e.g., distal) surface 283 a and a bottom (e.g., proximal) surface 283 b.

The gimbal 281 is disposed between the sensor body 68 and the support block 54. More specifically, the top surface 283 a of the gimbal 281 is in contact with the tubular portion 72 of the sensory body 68 and the bottom surface 283 b of the gimbal 281 is in contact with a distal surface of the support block 54. As the load sensing assembly 66 is compressed between the support block 54 and the connector sleeve 56, the support block 54 applies pressure on the gimbal 281. In additional to longitudinal pressure, lateral movement of the support block 54 is negated by the gimbal 281 due to its compression.

With respect to embodiments of FIGS. 17-23, the orientation of the sensory body 68, the gimbals 181 and 281, the concave and convex surface features may be reversed may be disposed distally of the sensor body 68 such that the interface is disposed distally of the sensory body 68. More specifically, the concave or convex surface features described above may be formed on the connector sleeve 56 and the top surface 78 of the sensory body 68 rather than the tubular portion 72.

With reference to FIGS. 11, 12, and 25, the load sensor circuit 86 is coupled to a signal processing circuit 90, which includes a flexible circuit board 92 having a contact portion 94 and a signal processing circuit portion 96. The contact portion 94 is interconnected with the signal processing circuit portion 96 via a flex strip 98 and includes a plurality of first pass-through contacts 100. The signal processing circuit 90 includes analog and digital circuit components (e.g., controller 130) that are configured to perform signal processing on signals from the load sensor circuit 86 and output a measurement signal to the handle assembly 20.

The flexible circuit board 92 may be any suitable dielectric multilayer flexible materials, such as PYRALUX® materials available from DuPont of Wilmington, Del., liquid crystal polymer materials, and the like. In embodiments, the flexible circuit board 92 may include additional dielectric layers, which stiffen the flexible circuit board 92 so that the solder connections of the components located along the flexible circuit board 92 are not subjected to unwanted movement due to thermal expansion and/or mechanical movement of the load sensing assembly 66. In embodiments, the flexible circuit board 92 may fabricated in a flat state (FIG. 25) and formed during soldering to sensor body 68 (FIG. 11). In further embodiments, the flexible circuit board 92 may be pre-bent using a fixture with or without heat to form the desired shape denoted in FIG. 11.

The contact portion 94 is configured to couple to the load sensor circuit 86, which includes one or more load sensing devices 102 interconnected by a plurality traces or other conductors. In embodiments, the load sensing devices 102 may be strain gauges, pressure sensors (e.g., pressure sensing film), or any other suitable transducer devices configured to measure mechanical forces and/or strain and output an electrical signal in response thereto. Signal output is achieved when the load sensing circuit 86 is bonded to the sensor body 68 such that the load sensing devices 102 are positioned in the respective areas of linear strain output when load sensing assembly 66 is elastically deformed.

The load sensor circuit 86 may be a single circuit board, such as a flexible circuit board with the load sensing devices 102 being disposed thereon and electrically interconnected via internal traces. The load sensing devices 102 are also electrically coupled via traces to a plurality of second pass-through contacts 101. In embodiments, the load sensing devices 102 may be attached to the first portion 74 of the platform 70 individually, rather than through the load sensor circuit 86 and then wired together to provide for electrical coupling.

The plurality of load sensing devices 102 may be arranged on the load sensor circuit 86 in a variety of configurations to achieve temperature compensation or other resistor networks, such as a Wheatstone Bridge in which two load sensing devices 102 are arranged to move in response to tension of the load sensing assembly 66 and two load sensing devices 102 are arranged to move in response to compression of the load sensing assembly 66. The configuration of four load sensing devices 102 as shown in FIG. 25 provides maximum signal output and temperature compensation and is known as a full bridge circuit.

With reference to FIG. 13, the first portion 74 also includes a pocket 104 having a gauging surface 106 for attachment of the load sensor circuit 86 and the contact portion 94 of the signal processing circuit 90. In embodiments, the load sensor circuit 86 may be bonded to the gauging surface 106 such that the signal processing circuit 90 outputs the measurement signal in response to the sensor body 68. The pocket 104 also includes a slot 108 having a plurality of pins 110 passing therethrough.

The slot 108 passes through the pocket 104 to the bottom surface 80 as shown in FIG. 11. The pins 110 are electrically coupled to the signal processing circuit 90 through a plurality of second pass-through contacts 101 (FIG. 25). In particular, when load sensor circuit 86 is bonded to the pocket 104, the second pass-through contacts 101 are inserted over pins 110. Thereafter the first pass-through contacts 100 of the contact portion 94 are also inserted over the pins 110. The first and second pass-through contacts 100 and 101 are aligned such that after soldering of the pins 110 thereto, the signal processing circuit 90 and the load sensor circuit 86 are electrically coupled to the pins 110 and each other. In embodiments, there may be four pins 110, with two of the pins 110 acting as communication lines and the remaining two pins 110 proving electrical power for energizing the load sensor circuit 86 and the signal processing circuit 90. After soldering, the flexible circuit board 92 can be arranged to fit within the cover 88.

In embodiments, the flexible circuit board 92 may be folded and/or bent as shown in FIGS. 11 and 12. In further embodiments, a support structure 112 may be disposed within the pocket 104. The support structure 112 includes one or more surfaces 114 onto which the flexible circuit board 92 is attached. The support structure 112 may have any suitable shape such that the flexible circuit board 92 is conformed to the shape of the support structure 112. The flexible circuit board 92 may be secured to the support structure 112 in any suitable manner, e.g., bonding, fasteners, etc.

In further embodiments, a wrap 116 can be disposed over the flexible circuit board 92 to insulate electronic components of the signal processing circuit portion 96 and prevent short circuits if the flexible circuit board 92 contacts an interior surface of the cover 88. The wrap 116 may be polyimide tape or ionomer resin tape, such as KAPTON® and SURLYN®, respectively, from DuPont of Wilmington, Del., shrink-wrap, polyisoprene membranes, low durometer potting compounds, parylene coatings, and other dielectric materials and applications suitable for insulating electronic circuits.

With reference to FIG. 10-13, the pins 110 are secured within a header 118, which hermetically seals the pocket 104 at the bottom surface 80. As shown in FIG. 24, each of the pins 110 is encased in a glass sleeve 120, each of which is then embedded in a peripheral housing 122. This construction seals the interior of cover 88 and the pocket 104 from the outside once the header 118 is bonded to slot 108 at the bottom surface 80 of the platform. The header 118 may be bonded (e.g., welded) to the bottom surface 80.

A hermetic seal may be formed by inserting the pins 110 through their respective glass sleeves 120, after which the pins 110 along with their glass sleeves 120 are inserted into corresponding bores of the peripheral housing 122 of the header 118. The entire assembly of the pins 110, glass sleeves 120, and the peripheral housing 122 are heated. Upon heating, the bore of the peripheral housing 122, which may be formed from any suitable metal (e.g., stainless steel), expands and the glass sleeves 120 fill the void. The pins 110 being formed from metal expand minimally and upon cooling, the glass sleeves 120 provide compression seals about their respective pins 110 and bores of the peripheral housing 122. As shown in FIG. 8, the pins 110 are the coupled to a flex cable 65, which in turn, is coupled to distal harness assembly 64.

With reference to FIG. 13, the pocket 104 further includes a step 124 along an entire perimeter of the pocket 104. The step 124 corresponds in size and shape to a flange 126 of the cover 88 as shown in FIGS. 14 and 15, to allow for creating of a hermetic seal. In addition, the flange 126 is configured to fit within the step 124 and is coplanar with the step 124. This allows for the flange 126 to sit on a flat surface portion of the step 124.

The cover 88 may be formed from a similar material as the sensor body 68. The cover 88 may be secured to the sensor body 68 in any suitable manner to ensure that the signal processing circuit 90 is hermetically sealed within the cover 88. In embodiments, the cover 88 and the sensor body 68 may be formed from a metal, such as stainless steel, and the cover 88 may be welded (e.g., by a laser) to the platform 70 around their respective perimeters. The cover 88 may be manufactured using a deep draw process, which provides for economical manufacturing. In embodiments, the sensor body 68 and the cover 88 may be manufactured using any suitable methods such as, machining, metal injection molding, 3-D printing, and the like.

With continued reference to FIGS. 14 and 15, the cover 88 includes a top wall 89, a pair of opposing side walls 91 a and 91 b, which are connected by a pair of opposing walls 93 a and 93 b. The walls 93 a and 93 b may have an arcuate shape to accommodate the signal processing circuit 90. In embodiments, the walls 89, 91 a, 91 b, 93 a, 93 b may have any suitable shape for enclosing the signal processing circuit 90. More specifically, the walls 89, 91 a, 91 b, 93 a, 93 b define an inner cavity 95, which fits over the signal processing circuit 90. The inner cavity 95 may also enclose the signal processing circuit 90 in a thermal management material. In embodiments, the inner cavity 95 may be filled with the thermal management material such as by using pre-metered injectors. The signal processing circuit 90, which is attached to the sensor body 68, is then inserted into the filled inner cavity 95, after which the cover 88 is secured to the sensor body 68 as described above. After the cover 88 is secured, the thermal management material may flow within the cavity 95 and the pocket 104, which is in fluid communication with the cavity 95.

With reference to FIGS. 25 and 26, the signal processing circuit 90 includes a controller 130 having a storage device 132, which may be an electrically erasable programmable read-only memory (“EEPROM”) or any other suitable non-volatile memory device. The controller 130 may be any suitable microcontroller or any other processor, such as CORTEX® microcontrollers available from ARM of Cambridge, UK. The controller 130 may include analog-to-digital converters, digital-to-analog converters, timers, clocks, watchdog timers, and other functional components that enable the controller 130 to process the analog measurement signals from the load sensing devices 102. In particular, the controller 130 is configured to amplify the signal from the load sensing devices 102 of the load sensor circuit 86, filter the analog signal, and convert the analog signal to a digital signal. The controller 130 is also configured to transmit the digital signal to the main controller 38 of the handle assembly 20, which controls operation of the surgical device 10 based on the digital signal indicative of the sensed mechanical load.

The controller 130 is programmable to allow for adjustments to gain and offset parameters for processing the analog signal. In particular, the controller 130 stores a zero balance value and corresponding gain and offset parameters in the storage device 132. After assembly of the load sensing assembly 66, load sensor circuit 86 is calibrated. In embodiments, the load sensor circuit 86 may be recalibrated periodically to ensure accurate measurements. Calibration may be performed under zero balance, namely, when the load sensor circuit 86 is unloaded. If the load sensor circuit 86 is outputting any signal even in an unloaded state, or conversely, not outputting a sufficient signal in response to a loaded state, the controller 130 is programmed to compensate for such discrepancy. This is accomplished by adjusting gain and offset parameters of the controller 130, which allows the controller 130 to adjust the analog signal to correspond to the zero balance state. The controller 130 may be programmed through the main controller 38, which is coupled to the controller 130 through the pins 110 as described above.

It will be understood that various modifications may be made to the embodiments of the presently disclosed adapter assemblies. Therefore, the above description should not be construed as limiting, but merely as exemplifications of embodiments. Those skilled in the art will envision other modifications within the scope and spirit of the present disclosure. 

What is claimed is:
 1. An adapter assembly comprising: a tubular housing having a proximal end portion and a distal end portion and defining a longitudinal axis; and a load sensing assembly disposed within the tubular housing in contact between a proximal surface and a distal surface, each of the proximal surface and the distal surface is perpendicular to the longitudinal axis, the load sensing assembly configured to measure a load exerted on the tubular housing, the load sensing assembly including a sensor body, wherein at least one of the proximal surface or the distal surface includes a first surface feature and the sensor body includes a second surface feature engaging the first surface feature.
 2. The adapter assembly according to claim 1, wherein the first surface feature is a convex surface feature and the second surface feature is a concave surface feature.
 3. The adapter assembly according to claim 2, wherein the first surface feature is a ridge having a first curved cross-section.
 4. The adapter assembly according to claim 3, wherein the second surface feature is a groove having a second curved cross-section.
 5. The adapter assembly according to claim 4, wherein the first curved cross-section and the second curved cross-section have the same radius.
 6. The adapter assembly according to claim 5, wherein the sensory body is configured to pivot about a pivot axis that is transverse to a longitudinal axis defined by the sensory body.
 7. The adapter assembly according to claim 6, wherein the pivot axis is defined by the ridge and passes through each of center of the first curved cross-section and the second curved cross-section.
 8. The adapter assembly according to claim 1, wherein the first surface feature is a concave surface feature and the second surface feature is a convex surface feature.
 9. The adapter assembly according to claim 8, wherein the first surface feature is a groove having a first curved cross-section.
 10. The adapter assembly according to claim 9, wherein the second surface feature is a ridge having a second curved cross-section.
 11. The adapter assembly according to claim 10, wherein the first curved cross-section and the second curved cross-section have the same radius.
 12. The adapter assembly according to claim 11, wherein the sensory body is configured to pivot about a pivot axis that is transverse to a longitudinal axis defined by the sensory body.
 13. The adapter assembly according to claim 6, wherein the pivot axis is defined by the ridge and passes through each of center of the first curved cross-section and the second curved cross-section. 